This application is commonly owned with a related pending U.S. Patent Application, Ser. No. PCT/US 86/02617, filed Dec. 2, 1986, in the name of Michael E. Leckrone and entitled "ANGIOPLASTY CATHETER AND METHOD OF USE THEREOF".
1. Field of the Invention
The invention relates to laser angioplasty catheters which are adapted to be inserted into ducts within the body of a patient such as blood vessels including arteries and veins. The catheters of t he invention are adapted to penetrate and disintegrate blockages, obstructions, occlusions, etc., or the like within the ducts in which the catheters are inserted. Thus, the catheters of the invention enable laser energy transmitted by an optical fiber or a bundle of optical fibers to be released from the distal end of the catheter to disintegrate or vaporize obstructions within blood vessels such as plaque in coronary, femoral, and other arteries. In use of an embodiment of the laser angioplasty catheters, the distal end of the catheter is positioned adjacent to the obstruction such as an occlusion or arteriosclerotic plaque which is to be removed from the duct. Due to the intense and concentrated energy level of the laser energy, such as pulsed laser energy, the laser angioplasty catheter of the invention must be adapted to prevent the laser energy from intersecting the internal wall of the duct at an angle or to a degree which could result in the possibility of damaging the duct. In addition, fluids within the duct such as blood within a blood vessel must be prevented from interfering with the transmission and release of the laser energy at the distal end of the catheter. It is also necessary to have control of the rotational position of the distal end of the catheter with respect to the duct in order that the catheter may operate upon an obstruction within a duct regardless of its circumferential position of the obstruction within the duct.
2. Description of the Prior Art
It is known in the prior art to provide a laser angioplasty catheter having a flexible shaft adapted to be inserted into a duct such as a blood vessel with a single or solid optical fiber or a bundle of optical fibers extending through the shaft to adjacent the distal end thereof. Laser energy such as pulsed laser energy is delivered to the proximal end of the optical fiber bundle and is emitted from the distal end thereof. When the laser energy intersects a blockage within the blood vessel, the laser energy disintegrates or vaporizes the blockage. By the application of suction to a lumen extending through the shaft, debris resulting from the disintegration or vaporization of the blockage can be withdrawn from the blood vessel
U.S Pat. No. 4,627,436, issued Dec. 9, 1986, discloses a laser angioplasty catheter in which laser energy is delivered to a cavity or jaw formed by spaced abutments at the outer portion of the catheter adjacent to the distal end thereof. An inflatable balloon disposed opposite the abutments can be controllably inflated to urge the abutments toward the inner surface of the duct and thereby receive the blockage with the jaw between the abutments. Laser energy is emitted by the distal end portion of an optical fiber or fibers into the jaw in order to vaporize the blockage. The abutments adjacent to the distal end of the catheter prevent the laser energy from being propagated downstream of the distal end of the catheter and thereby prevent the laser energy from contacting the inner surface of the duct. A passage extending through the length of the catheter is adapted to apply suction to the jaw disposed between the abutments in order to remove debris therefrom. By rotating the catheter from the proximal end thereof, the distal end portion of the catheter can be rotated in order to position the abutments and the jaw therebetween within the circumference of the inner surface of the duct.
U.S. Pat. No. 4,685,458, issued Aug. 11, 1987, which is a division of U.S. Pat. No. 4,627,436, discloses a catheter similar to that of the 4,627,436 patent, but with an elongated element such as a cutting blade or a hot-wire extending between the abutments and adjacent to the jaw therebetween. The blade or hot-wire is adapted to cut or sever a blockage from the inner surface of the duct rather than to vaporize the obstruction by the application of laser energy.
U.S. Pat. No. 4,207,874, issued June 17, 1980, is another example of a laser angioplasty catheter. In this catheter, laser energy disintegrates or vaporizes an obstruction and suction is applied to a passage extending through the length of the catheter to withdraw debris produced by the application of the laser energy.
U.S. Pat. No. 4,573,470, issued Mar. 4, 1986, and U.S. Pat. No. 4,582,181, issued April 15, 1986, each disclose a steerable balloon dilation catheter in which the distal end of the tubular member of the catheter is bonded to the distal end of a core wire.